You bet they are. I ride the occasional time trial at distances up to 100 miles and my times are similar to what I did forty years ago. I've never had my power output measured but I'm certain it is way, way down. Judging by the way I climb and sprint it could be as low as half of what it was. I use Mavic 20 spoke wheels and tri-bars and a regular helmet, despite the paunch I wear a skin suit. Once I'm in cruising mode on a flat road I can convince myself I'm still a racer and I am certain the wheels play a big part. The rest of the bike is on topic. Ray Green, Brighton England
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